Mandibular midline distraction osteogenesis: a complex case with severe crowding.

This article reports on a patient with severe maxillary and mandibular crowding treated by both expansion and extraction treatment. Two surgical procedures, surgically assisted palatal expansion and a mandibular midline osteotomy, were performed in sequence for skeletal expansion. A hybrid appliance, consisting of a Hyrax screw and 2 miniplates, was used in the mandible. Since expansion was not enough for relief of the crowding, 3 premolars were later extracted. The patient's final occlusion was satisfactory, but genioplasty may be desired in the future.